Still quite cold, can definitely get on some good whiting runs then but it just depends and they can be very picky about what they'll hit. I've filled coolers March 30-31 before (and had guys get pretty annoyed when they're not catching with their pier house rigs and frozen-brined-crappy shrimp) and the same dates have been too early some years. Could be some bluefish as well. They'll eat last year's frozen mullet well if they're around but they'll be skinny.
Clear nosed skates and dogfish should be plentiful depending on water temps. Rarely a few small Spanish will be biting that early on tree rigs. Some years they won't show up for 2-3 more weeks. No live bait to be had in the surf except glass minnows (not gonna do you any good) unless you count a croaker or small whiting. Sand fleas will be there but probably deep and will take a good bit of digging around (assuming there are any on the beach you're at). You can buy live mud minnows (or trap your own inshore) and can catch some trout or red drum right in the suds but you won't load the cooler.
Some tips if you really want to catch fish:
Buy the best eating quality raw shrimp you can find if you really want to catch.
You don't HAVE to for whiting but it definitely won't hurt if you hand tie your rigs out of fluoro...I use 25 lb Seaguar and #4 circle hooks.
Blues are usually small but hungry, smaller pieces of cut bait especially strips of fillets will get them. Upsize your rigs a bit if they are thick.
There is no "fresh" IE never frozen local shrimp until June-August sometime but don't buy frozen crap from a pier or bait shop. Go to a grocery store or seafood market. I've spent $13/lb for the best looking shrimp I could find and caught 15 to 1 against the other guys on the piers using the tubs of shrimp. They gave me some looks and shook their heads when I told them I was just using shrimp when they asked about my baits.
Get some live clams for bait while you're at a seafood market if surf fishing.
Warm enough to find some black drum on shrimp and clams, too, preferably if you're near structure (under a pier or near rocks).
If off of a pier try cut bait for northern whiting as well - they're usually in the deeper water off the end of the piers and some years they hit 1/4-1/2" cubes of bluefish fillets very well. In the surf those whiting are generally the gulf and southern whiting and they prefer shrimp, clams, and sand fleas.
Let me know if I can help more.
